A use right of each application has heretofore been granted by causing a licenser to issue a serial number for each user and each user to input a serial number issued upon installation of the application or at the startup of the application, thereby performing authentication. A logic for checking that the input serial number has been issued from the licenser has been incorporated in the application in this case, thereby preventing the unauthorized use of the application.
The granting of the right of use by such a serial number as described above is accompanied by problems such as a case where the same serial number is shared with a plurality of persons to use the application thereamong, a case where an unauthorized person steals a look at the serial number and uses it, etc.
As a technology for solving such problems, there has been known a method using a method for checking the status of use of an application through the use of the Internet. This method is of a method based on the premise that a PC of a user and a server of a licenser are connected to each other via the Internet, thereby enabling mutual communication. This method shows that an application made available using a serial number regularly transmits user information, a serial number and use environment information (such as OS, IP address, device configuration information) to the server, and the server manages the number of use rights of every user and checks for consistency with regularly-sent use information. This method is thus capable of detecting unauthorized use of the application and performing a restriction on its use and its use suspension as needed.
The aforementioned method is incapable of detecting the unauthorized use if the user's PC is not connected to the Internet and providing the use of the application by a user having a regular right of use. Therefore, a technology for checking a use right of an application and its use status through the use of a portable telephone has been described and proposed in, for example, patent document 1 or the like. The prior art described in the patent document 1 utilizes a user's portable telephone like a repeater with respect to a PC disconnected from the Internet and connects the PC and a server via the portable telephone, thereby making it possible to check for grant of a use right of an application and its use status from the server.    Patent Document 1: Japanese Patent Application Laid-Open No. 2006-309720